Fujitsu microcontroller (8-Bit) Clock Modes Problems

[Chris]

Hi,

I'm programming on a Fujitsu Microcontroller from the MB95Fxxx family
and I'm trying to switch the clock modes. (I'm using the MB95
So I can switch from MAIN-PLL Clock to SUB-PLL Clock without any
problems but I can not switch from SUB-PLL to MAIN-PLL correctly...

I managed to isolate the prob: to switch the clock modes we only have
2 registers (SYCC (0x07) and PLLC (0x06)).
If I read the value back (I copied them into a variable) and compare
them with the values in the memory map, respectively on address 0x06
and 0x07, the values don't correspond !

Code to switch from SUB-PLL to MAIN-PLL Code

PLLC_MPEN = 1;
While (!PLLC_MPRDY); /* the program waits here */

The Symbol PLLC_MPRDY is 0, but the corresponding bit in memory at
address 0x06 is set !
So the program works and switch every 2s in one of both modes. (I
checked if the quartz were oscillating)

Does someone already have this problem ? or have a solution ?

Thanks

Chris

 

[Jasen Betts]

Hi,

I'm programming on a Fujitsu Microcontroller from the MB95Fxxx family
and I'm trying to switch the clock modes. (I'm using the MB95
So I can switch from MAIN-PLL Clock to SUB-PLL Clock without any
problems but I can not switch from SUB-PLL to MAIN-PLL correctly...

I managed to isolate the prob: to switch the clock modes we only have
2 registers (SYCC (0x07) and PLLC (0x06)).
If I read the value back (I copied them into a variable) and compare
them with the values in the memory map, respectively on address 0x06
and 0x07, the values don't correspond !

Code to switch from SUB-PLL to MAIN-PLL Code

PLLC_MPEN = 1;
While (!PLLC_MPRDY); /* the program waits here */

The Symbol PLLC_MPRDY is 0, but the corresponding bit in memory at
address 0x06 is set !
So the program works and switch every 2s in one of both modes. (I
checked if the quartz were oscillating)

Does someone already have this problem ? or have a solution ?

perhaps you are misusing the symbol, maybe it should be used something
like this:

PLLC_MPEN = 1;
while(!(PLLC_MPEN & (1<<PLLC_MPRDY))){ /* wait */};

 

[Chris]

perhaps you are misusing the symbol, maybe it should be used something
like this:

PLLC_MPEN = 1;
while(!(PLLC_MPEN & (1<<PLLC_MPRDY))){ /* wait */};

Hi,

It works ! That was the problem !
Thanks for the answer

bye

Chris

 

[Chris]

Hi,

It works ! That was the problem !
Thanks for the answer

bye

Chris

Hi,

bad news, PLLC_MPRDY is equal to 0, so the bit won´t be shiffted. So I
´m already at the first position... At the first position (of the
Byte) is another bit that is already set...The Condition is already
true....

I will check the symbol list....

Chris

 

[Nobody]

Code to switch from SUB-PLL to MAIN-PLL Code

PLLC_MPEN = 1;
while (!PLLC_MPRDY); /* the program waits here */

What are PLLC_MPEN and PLLC_MPRDY? Did you define them, or are they
part of the SDK?

From how you have used them, I'm guessing that they're individual bits
within the registers, implemented as macros which expand to
bitfields in a structure located at a specific address, e.g.:

struct pllc {
unsigned sprdy : 1;
unsigned spmc : 2;
unsigned spen : 1;
unsigned mprdy : 1;
unsigned mpmc : 2;
unsigned mpen : 1;
} *pllc_reg = (struct pllc *) 0x0006;

#define PLLC_MPEN (pllc_reg->mpen)
#define PLLC_MPRDY (pllc_reg->mprdy)

OTOH, if they are just bitmasks, then you are using them wrong; you would
need e.g.:

#define PLLC (*(volatile unsigned char *)0x0006)
#define PLLC_MPEN 0x80
#define PLLC_MPRDY 0x10

PLLC |= PLLC_MPEN;
while (!(PLLC & PLLC_MPRDY)) ;

If you have enabled optimisations, the compiler will need the underlying
variable to have been labelled as "volatile", as its value will change
even when the CPU is in a busy-wait loop.

The Symbol PLLC_MPRDY is 0, but the corresponding bit in memory at address
0x06 is set !

It sounds as if you might not be using the macros correctly. How about
posting their definitions?

 

[Jasen Betts]

Hi,

bad news, PLLC_MPRDY is equal to 0, so the bit won´t be shiffted. So I
´m already at the first position... At the first position (of the
Byte) is another bit that is already set...The Condition is already
true....

I will check the symbol list....

Possibly you need to use a symbol other than PLLC_MPEN in the second
line. you may have to go to the datasheet for the processor to find
out what the name of the register that holds the apropriate bit is
called.

 

[Chris]

Possibly you need to use a symbol other than PLLC_MPEN in the second
line. you may have to go to the datasheet for the processor to find
out what the name of the register that holds the apropriate bit is
called.

Hi,

Thank you for the answers
The microcontroller, which I´m working with, is the Fujitsu MB95F168.

@Jasen: you are right, the MPEN symbol should not be used in the
second line: I found an application note with following code example:

MPEN = 1;
while(IO_PLLC.bit.MPRDY ==0) {;}

Sounds similar to the code I wrote...

@Nobody: The optimizations are deactivated.
You are right, the individual bits within the registers, are
implemented as macros which expand to
bitfields in a structure located at a specific address.
I also posted the IO-Definitions. (they were given from manufacturer.)

typedef union{ /* PLL */
IO_BYTE byte;
struct{
#if defined(__BITFIELD_ORDER_MSB__)
IO_BYTE _MPEN :1;
IO_BYTE _MPCM1 :1;
IO_BYTE _MPCM0 :1;
IO_BYTE _MPRDY :1;
IO_BYTE _SPEN :1;
IO_BYTE _SPMC1 :1;
IO_BYTE _SPMC0 :1;
IO_BYTE _SPRDY :1;
#else
IO_BYTE _SPRDY :1;
IO_BYTE _SPMC0 :1;
IO_BYTE _SPMC1 :1;
IO_BYTE _SPEN :1;
IO_BYTE _MPRDY :1;
IO_BYTE _MPCM0 :1;
IO_BYTE _MPCM1 :1;
IO_BYTE _MPEN :1;
#endif
}bit;
struct{
#if defined(__BITFIELD_ORDER_MSB__)
IO_BYTE :1;
IO_BYTE _MPCM :2;
IO_BYTE :2;
IO_BYTE _SPMC :2;
#else
IO_BYTE :1;
IO_BYTE _SPMC :2;
IO_BYTE :2;
IO_BYTE _MPCM :2;
#endif
}bitc;
}PLLCSTR;

__IO_EXTERN __io PLLCSTR _pllc; /* PLL */
#define PLLC _pllc.byte
#define PLLC_SPRDY _pllc.bit._SPRDY
#define PLLC_SPMC0 _pllc.bit._SPMC0
#define PLLC_SPMC1 _pllc.bit._SPMC1
#define PLLC_SPEN _pllc.bit._SPEN
#define PLLC_MPRDY _pllc.bit._MPRDY
#define PLLC_MPCM0 _pllc.bit._MPCM0
#define PLLC_MPCM1 _pllc.bit._MPCM1
#define PLLC_MPEN _pllc.bit._MPEN
#define PLLC_SPMC _pllc.bitc._SPMC
#define PLLC_MPCM _pllc.bitc._MPCM

I thought that I could use the PLLC_MPRDY to check if the MAIN-PLL
Clock has been stabilized or not... Even if I use _pllc.bit._MPRDY, as
suggest in the example, I don´t have the right value from memory...

The complete IO-Map Header File can be downloaded here:
http://mcu.emea.fujitsu.com/mcu_product/detail/MB95F168JPMC.htm

Thanks for the answers !

Chris

 

[Nobody]

I thought that I could use the PLLC_MPRDY to check if the MAIN-PLL
Clock has been stabilized or not...

From my reading of the data sheet and the above, I would have thought that
too.

Even if I use _pllc.bit._MPRDY, as
suggest in the example, I don´t have the right value from memory...

So you're saying that PLLC_MPRDY (or _pllc.bit._MPRDY) doesn't match:

*((unsigned char *)6)>>4&1

?

Does "(int)&_pllc == 6" hold?

Does creating your own PLLCSTR instances behave as expected, e.g.:

PLLCSTR my_pllc;
my_pllc.byte = 0;
my_pllc.bit._MPRDY = 1;
printf("0x%02x", (unsigned int) my_pllc.byte);
?

[Note: the above needs to have all optimisations disabled, as using both
the .bit and .byte fields of the union violates ANSI C aliasing rules.]

Does testing _pllc.byte rather than an explicit memory location work?